//运算符
main() {
  // 算术运算符
  print(1 + 2);
  print(1 - 2);
  print(1 * 2);
  print(1 / 2);
  print(10 ~/ 3); //取整
  print(10 % 3); //取余
  // 关系运算符
  print(1 == 2);
  print(1 != 2);
  print(1 > 2);
  print(1 < 2);
  print(1 >= 2);
  print(1 <= 2);

  //赋值运算符
  double a = 1;
  a += 2;
  print(a);
  a -= 2;
  print(a);
  a *= 2;
  print(a);
  a /= 2;
  print(a);
  a %= 2;
  print(a);

  //自增自减
  int age = 18;
  age++;
  print(age);
  age--;
  print(age);

  //逻辑运算符
  print(true && false);  //false
  print(true && true);  //true
  // print(true || false);  //true
  print(false || true);  //true
  print(!false);  //true
  print(!true);  //false


  num price = 19.99999;
  print(price.toStringAsFixed(2));  //20
}
